Digital Signals Flashcards
Regardless of whether a signal is analog or digital, one of the key specifications to factor into an AV design is _____.
bandwidth
_____ is the visual representation or pattern of a digital signal.
Eye pattern
An unencoded audio signal’s bandwidth requirements are in direct relationship to the signal’s _____ and _____.
sampling rate (measured in hertz) and bit depth (measured in bits)
The formula for the required data throughput of a single unencoded audio stream is as follows:
Sampling Rate × Bit Depth × Number of Channels = Bit Rate (bps)
Common audio sampling rates include the following:
Telephone
A. 8kHz B. 44.1 kHz C. 48 kHz D. 96 or 192 kHz E. 2.8 MHz
A. 8kHz
Common audio sampling rates include the following:
Audio CD
A. 8kHz B. 44.1 kHz C. 48 kHz D. 96 or 192 kHz E. 2.8 MHz
B. 44.1 kHz
Common audio sampling rates include the following:
DVD Audio
A. 8kHz B. 44.1 kHz C. 48 kHz D. 96 or 192 kHz E. 2.8 MHz
C. 48 kHz
Common audio sampling rates include the following:
Blue-ray Disc
A. 8kHz B. 44.1 kHz C. 48 kHz D. 96 or 192 kHz E. 2.8 MHz
D. 96 or 192 kHz
Common audio sampling rates include the following:
Super Audio CD (SACD)
A. 8kHz B. 44.1 kHz C. 48 kHz D. 96 or 192 kHz E. 2.8 MHz
E. 2.8 MHz
The formula for black-and-white, uncompressed digital video signal bandwidth is as follows:
Horizontal pixels × Vertical pixels × Bit depth × Frames per second = Bit rate (bps)
A 4:4:4 color video signal requires ____ times the bandwidth of its black-and-white counterpart.
three
The formula for three-channel, uncompressed digital video signal bandwidth is as follows:
Horizontal pixels × Vertical pixels × Bit depth × Frames per second × 3 = Bit rate (bps)
Computers have a transparency layer called a(n) _____.
alpha channel
The formula for four-channel uncompressed digital video signal bandwidth is as follows:
Horizontal pixels × Vertical pixels × Bit depth × Frames per second × 4 = Bit rate (bps)
____ sampling uses all three signals in equal proportion.
A. 4:4:4
B. 4:2:2
C. 4:2:0
D. 4:1:1
A. 4:4:4
____ sampling includes all the luminance information, but only half the red and blue channels.
A. 4:4:4
B. 4:2:2
C. 4:2:0
D. 4:1:1
B. 4:2:2
____ sampling includes all the luminance information, but only one-fourth of the color information is sampled.
A. 4:4:4
B. 4:2:2
C. 4:2:0
D. 4:1:1
D. 4:1:1
____ sampling is used for broadcast TV.
A. 4:4:4
B. 4:2:2
C. 4:2:0
D. 4:1:1
B. 4:2:2
The formula for 4:2:2 digital video signal bandwidth is as follows:
Luminance + Cr + Cb= Bit rate (bps)
where
- Luminance = Frames per second × Bit depth × Horizontal pixels × Vertical pixels
- Cr (red) = Frames per second × Bit depth × 1/2 Horizontal pixels × Vertical pixels
- Cb (blue) = Frames per second × Bit depth × 1/2 Horizontal pixels × Vertical pixels
The formula for 4:1:1 digital video signal bandwidth is as follows:
Luminance + Cr + Cb = Bit rate (bps)
where
- Luminance = Frames per second × Bit depth × Horizontal pixels × Vertical pixels
- Cr (red) = Frames per second × Bit depth × 1/4 Horizontal pixels × Vertical pixels
- Cb (blue) = Frames per second × Bit depth × 1/4 Horizontal pixels × Vertical pixels
____ sampling is mathematically the same as 4:1:1 sampling in terms of required bandwidth, with basically the same color resolution and a different pixel pattern.
4:2:0
AV Program Bandwidth formula:
Video bit rate + Audio bit rate + Overhead = Total required bandwidth (bps)
With _____ compression, the AV data is the same after it’s been compressed and decompressed as it was originally. All the data remains intact.
A. Lossless
B. Lossy
A. Lossless
_____ compression techniques compress and discard “unneeded” data while still returning an acceptable-quality stream after decoding. The compression program examines a video or audio segment for detail that is less important or less noticeable.
A. Lossless
B. Lossy
B. Lossy
JPEG and H.264 are examples of _____ video compression.
A. Lossless
B. Lossy
A. Lossless
Advanced Audio Coding (AAC) and MPEG-1 or MPEG-2 audio layer 3 (MP3) are examples of _____ audio compression.
A. Lossless
B. Lossy
B. Lossy
MPEG-2 and VC-1 are examples of ______ video compression.
A. Lossless
B. Lossy
B. Lossy
The software or hardware that actually performs the lossless or lossy compression—as well as the decompression—is the ______.
codec
Codec is short for _____.
encoder/decoder
_____ is one of the more common audio encoding formats.
MP3
MP3 uses a _____ compression algorithm that reduces or discards the auditory details that most people can’t hear, drastically reducing overall file sizes.
lossy
The ____ format includes bit rates ranging from 32 to 320 kbps, with available sampling rates of 32 kHz, 44.1 kHz, and 48 kHz.
A. MP3
B. MPEG-1
C. MPEG-2
D. AAC
B. MPEG-1
The ____ format includes bit rates ranging from 8 to 160 kbps, with available sampling rates of 16 kHz, 22.05 kHz, and 24 kHz.
A. MP3
B. MPEG-1
C. MPEG-2
D. AAC
C. MPEG-2
MP3 encoding may be accomplished using _____ or _____ methods.
constant bit rate (CBR) or variable bit rate (VBR) methods.
_____ encoding uses a lower bit rate to encode portions of the audio that have less detail, such as silence, and uses a higher bit rate to encode more complex passages.
A. Constant bit rate
B. Variable bit rate
C. MPEG-1
B. MPEG-2
B. Variable bit rate
_____ has more information than ______, the resulting files and streams are much larger.
A. Audio / Video
B. Video / Audio
B. Video / Audio
_____ compresses and sends each frame individually. Because it sends each individual frame, it is preferable for editing video.
A. Interframe compression
B. Intraframe compression
C. Outerframe compression
D. Extraframe compression
B. Intraframe compression
_____ detects how much information has changed between frames and sends a new frame only if there are significant differences. It requires less bandwidth to stream and results in smaller files.
A. Interframe compression
B. Intraframe compression
C. Outerframe compression
D. Extraframe compression
A. Interframe compression
Motion JPEG uses _____.
A. Interframe compression
B. Intraframe compression
C. Outerframe compression
D. Extraframe compression
B. Intraframe compression
MPEG video algorithms use _____.
A. Interframe compression
B. Intraframe compression
C. Outerframe compression
D. Extraframe compression
A. Interframe compression
Most videoconferencing codecs use _____.
A. Interframe compression
B. Intraframe compression
C. Outerframe compression
D. Extraframe compression
A. Interframe compression
When it comes to encoding and decoding a digital signal, video frames are formed into logical groups, known as ______.
groups of pictures (GoPs)
A _____ is a set of video frames, which, when played in succession and in line with others, creates the video stream
groups of pictures (GoPs)
In a GoP, there are three picture types, _____, _____, and _____.
I-frames (intraframes), P-frames (predictive frames), and B-frames (bidirectional frames)
In a GoP, the ______ frames are complete reference pictures. Every GoP starts with this frame.
A. I-frames
B. P-frames
C. B-frames
D. C-frames
A. I-frames
In a GoP, the ______ frames contain information about how the frame is different from the preceding frame.
A. I-frames
B. P-frames
C. B-frames
D. C-frames
B. P-frames
In a GoP, the ______ frames contain information about how the frame is different from the preceding and following frames.
A. I-frames
B. P-frames
C. B-frames
D. C-frames
C. B-frames